Antoniou K, Papathanasiou G, Papalexi E, Hyphantis T, Nomikos G G, Spyraki C, Papadopoulou-Daifoti Z
Department of Pharmacology, Medical School, University of Ioannina, 45110 Ioannina, Greece.
Behav Brain Res. 2008 Mar 5;187(2):462-72. doi: 10.1016/j.bbr.2007.10.010. Epub 2007 Oct 22.
Experimental animals can be differentiated on the basis of their horizontal or vertical activity to high responders (HR) and low responders (LR) upon exposure to a novel environment. These individual differences have been associated with behavioral and neurobiological differences in a number of experimental procedures used for studying sensitivity to psychostimulants, anxiety, depression, and cognitive function. In the present study, we differentiated the rats to HR and LR based on their vertical activity upon exposure to a novel environment. Additionally, we ascertained whether HR and LR rats differ in a battery of tests such as passive avoidance (PA), object recognition (OR), and the water-maze (WM) that provide indices for cognitive function and the forced swim test (FST), an animal model of affective responsivity and antidepressant-like activity. Potential differences in neurochemical indices between the two phenotypes were also examined. HR rats displayed impaired non-spatial object recognition memory, but enhanced spatial performance, as compared to LR rats. FST induced "depressive-like" symptoms in both phenotypes that were differently manifested in HR versus LR rats. Neurochemical findings revealed distinct differences in serotonergic and dopaminergic activity in the striatum and the prefrontal cortex of HR as compared to LR rats. The above results show that HR and LR rats exhibit important differences in a battery of tests related to cognitive performance or affective responsivity, which may be associated with differences in certain neurobiological parameters.
实验动物在接触新环境时，可根据其水平或垂直活动分为高反应者（HR）和低反应者（LR）。在许多用于研究对精神兴奋剂、焦虑、抑郁和认知功能敏感性的实验过程中，这些个体差异与行为和神经生物学差异有关。在本研究中，我们根据大鼠在接触新环境时的垂直活动将其分为HR和LR。此外，我们确定了HR和LR大鼠在一系列测试中是否存在差异，如被动回避（PA）、物体识别（OR）和水迷宫（WM），这些测试可为认知功能提供指标，以及强迫游泳测试（FST），这是一种情感反应和抗抑郁样活动的动物模型。我们还检查了两种表型之间神经化学指标的潜在差异。与LR大鼠相比，HR大鼠表现出非空间物体识别记忆受损，但空间表现增强。FST在两种表型中均诱发了“抑郁样”症状，在HR大鼠和LR大鼠中的表现有所不同。神经化学研究结果显示，与LR大鼠相比，HR大鼠纹状体和前额叶皮质中的血清素能和多巴胺能活动存在明显差异。上述结果表明，HR和LR大鼠在一系列与认知表现或情感反应相关的测试中表现出重要差异，这可能与某些神经生物学参数的差异有关。
